97 KDX engine ran away

[catfood]

Installed a new PC2 pipe this weekend and had the bike suddenly rev without being able to control throttle, clutch did not disengage, and kill switch did not work. Got lucky and locked up the bike which killed the engine. Can use some advice on this. Am I having problems with sudden lean condition? Never happened with stock pipe.
:whoa:

 

[ebeck]

What does the lean condition have to do with the lack of throttle control? Sounds like 2 seperate issues. Is the throttle cable kinked?

 

[mandark1967]

Installed a new PC2 pipe this weekend and had the bike suddenly rev without being able to control throttle, clutch did not disengage, and kill switch did not work. Got lucky and locked up the bike which killed the engine. Can use some advice on this. Am I having problems with sudden lean condition? Never happened with stock pipe.
:whoa:

The pipe itself has nothing to do with the sticking throttle. Sounds like you kinked the throttle cable when you installed the pipe...

 

[catfood]

Throttle cable was not kinked nor did it show any other damage. I was riding a trail, suddenly realized that the engine would not rev down. Throttle seemed to move with no binding feel when it happened. Pilot jet is 45, main is 155. 50 to 1 mix MC-1. Thought lean condition because of experience with small two stroke motors when they ran out of fuel. Also really woke up the bike with the PC2 pipe and question if it may have any effect on the bike revving up unexpectedly.

 

[ebeck]

When the throttle closes the fuel flow stops. If the throttle won't close then it is a throttle problem.

The pipe has no effect on "unexpectd" reving.

 

[catfood]

Alright back to the basics. Will check again throttle linkage, cable and clean the carb. Thanks for the replies.

 

[paab]

Take the top off the carb and make sure the spring collar nub is seated in the slot...

 

[joebiodiesel]

I don't pretend I know what happened to your bike, but I know that when my jetting is right on the money, or a little lean, my 2 strokes will run away when coming off a high rev with no load. They'll scream until you load them or kill the ignition. I've seen it on my snowmobile, motorcycle and my boat. My boat, a 200HP Merc Black Max has a factory ignition kill box on it for that exact reason. If the vacuum goes high it kills the spark until it idles.
If I had to guess, I might think that the pipe leaned it out, you had a no-load run away and just got a little confused about the kill switch and clutch not working during the panic. I'd check my jetting to be sure it's not too lean before putting too many hours on it.
Good luck,
Joe

 

[76GMC1500]

No load runaways are caused by air leaks. Loaded runaways are caused by stuck throttles. Check for smooth operation of the slide in the carb, the throttle cable, CHECK the throttle cable freeplay, etc...

 

[krazyinski]

mine does that if I forget to turn the fuel on.

 

[radonc73]

Take your throttle housing off at the bar and clean the crap inside out. Mine had alot of fine dust built up in it and check the throttle slide for marks.

 

[catfood]

I appreciate all the replies. The bike is parked until I can work through the suggestions on all the posts. Many thanks. :cool: